Rotary mower blade



Feb. 16; 1954 M. M. WARREN ROTARY MOWER BLADE Filed June 18, 1952INVENTOR ATTORNEYS Patented Feb. 16, 1954 UNITED STATES PATENT OFFICEROTARY MOWER BLADE Madden M. Warren, Atlanta, Ga., assignor of one-halfto Guy M. Kirby, College Park, Ga.

1 Claim.

Th s invention relates to a cutting blade for a rotary lawnmower.

An object of this invention is to provide an improved cutting blade fora rotary lawnmower wherein a pair of cutting blades are pivotallymounted on a carrier, and are adapted to centrifugally swing outwardlyto cutting position.

Another object of this invention is to provide an improved cutting bladefor a rotary lawnmower which is so constructed and arranged that thecutting blades upon striking a hard object may pivot on the carrier, sothat the power unit and the drive mechanism will not be damaged.

A further object of this invention is to provide a cutting bladeassembly wherein the blades may be easily and quickly removed andreplaced.

With the above and other objects in view, my invention consists in thearrangement, combination and details of construction disclosed in thedrawing and specification, and then more particularly pointed out in theappended claim.

In the drawing:

Figure 1 is a plan view of a cutter assembly for use with a rotarylawnmower constructed according to an embodiment of this invention.

Figure 2 is a detailed side elevation of the device.

Figure 3 is an enlarged end elevation of the device.

Figure 4 is an enlarged fragmentary sectional view taken on the line 4-4of Figure 1.

Referring to the drawing, the numeral l designates generally anelongated bar which constitutes a blade carrier and is provided with anopening is in the center thereof by means of which the carrier [0 may besecured to a vertically disposed drive shaft forming part of themechanism for a rotary lawnmower. The bar or carrier it is provided ateach end thereof and on the lower side with a block I I which is weldedor otherwise fixedly secured to the bar It.

The bar It and block I l have an opening I 2 therethrough within which acylindrical bushing I is mounted. The bushing l4 extends below the blockH and a cutter generally designated as 15 is rotatably mounted about thelower end of bushing It. A thrust washer I6 is disposed about bushing Itbetween block II and the upper side of cutter i5, and a second thrustwasher I1 is disposed below the cutter l and engages about the shank ofa bolt l8.

The washer l1 bears against the lower end of bushing l4 and an upper nutl9 threaded on bolt I 8 bears against the upper end of bushing 14. Alock nut 20 threaded on bolt l8 holds nut [9 in locked position on boltl8. There is a slight space between the cutter l5 and the two washers l6 and I! so that cutter l 5 can freely rotate about bushing l4. Cutter[5 is formed of a flat plate 2| having a keen edge 22 and an upturnedtrailing edge 23. The upward curvature 23 of plate 2| provides a meanswhereby an upper draft of air will be created causing grass to standerect and meet cutting edge 22 and also blow the grass upwardly.

In addition, the upward curvature of plate 2| will cause the cut grassto slide upwardly over the concave upper side of the trailing curvedportion 23, which causes the grass to be struck more than once by thecutting edge 22, thereby resulting in the creation of a mulch.

In the use and operation of this blade assembly, the carrier I0 isfirmly secured to the drive shaft of the mower with carrier in disposedin a horizontal position. As carrier [0 is rotated, cutting blades 5will swing outwardly by centrifugal force to substantially the positionshown in Figure 1.

In the event a relatively hard object is struck by one or more of theblades I5, these blades may swing inwardly under the impact of the blade25 with the object, so that the drive shaft and other comprising anelongated carrier, bushing form-' ing means at each end of said carrier,a cutting blade at each end of said carrier, means extending throughsaid blades and bushings pivotally mounting said blades on said carrier,each blade being formed of a rectangular plate having a keen leadingedge and an arcuately upturned parallel trailing edge, said upturnededge tapering downwardly to the level of the plate at the inner edgethereof.

MADDEN M. WARREN.

References Cited in the file of this patent UNITED STATES PATENTS NameDate Junge June 4, 1940 soenksen Apr. 15, 1952 Number

